The present invention relates to a coated metal tubing and fitting assembly, and particularly to a method of securing a fitting to an end of a coated tube.
It is often desirable to coat steel tubes with nylon or other materials in order to provide corrosion resistance; however, this presents an additional problem. Although the coating may be only 0.005 or 0.006" thick, this increase in diameter is sufficient to prevent the use of standard end fittings with the coated tubes. One proposed solution has been to provide non-standard end fittings, which include a larger inner diameter to accommodate the thickness of the coating. However, the additional expense of tooling and producing limited production non-standard end fittings to be used only for coated tubes is undesirable. Similarly, it would be impractical to provide non-standard tube sizes which when coated would fit standard end fittings. Another proposed solution has been to remove the coating from the ends of the tube in order to accommodate the end fitting. However, removal of coating from the ends of the coated tube is also costly and impractical.